Gas turbine engine components are often exposed to high temperatures. For instance, the turbine section of a gas turbine engine may include blade outer air seals circumferentially surrounding the turbine blades. The blade outer air seals may include a coating to protect from erosion, oxidation, corrosion or the like from hot exhaust gas flowing through the turbine section. In particular, conventional blade outer air seals may include ceramic coatings, metallic coatings, or both.
A drawback of conventional coatings and blade outer air seals in general, is vulnerability to cracking and coating spall. For example, blade outer air seals may include internal cooling passages or back-side impingement cooling to resist the high temperatures of the hot exhaust gases. However, the cooling may produce a considerable thermal gradient through the seals that may cause accelerated seal corrosion and coating/seal cracking to open the cooling passages.